header {
    height: 100px;
    width: 1000px;
    margin: 0 auto;
}
li {
    float: left;
    line-height: 100px;
    padding: 0 10px;
}
.logo {
    float: left;
}
.logo img {
    height: 100px;
}
nav ul {
    float: left;
}
header nav {
    float: left;
}
header .user {
    float: right;
}

.user ul:first-child {
    display: block;
}
.user ul:last-child {
    display: none;
}

.islogin ul:first-child {
    display: none;
}
.islogin ul:last-child {
    display: block;
}
